CAPE ELIZABETH – Race founder Joan Benoit Samuelson is proud of the impact the Beach to Beacon 10K road race has had on the local running community, but even she was stunned by what she witnessed one evening last week.

“I couldn’t believe how many people were running the course,” Samuelson said. “It was just incredible. All shapes, sizes, descriptions. Some were walking. Some were running really hard. There were large groups. There were individuals. There were father-sons, mother-daughters. Bands of women. Bands of men.

“It has really transcended the sports and transcended my wildest dreams and expectations.”

Samuelson’s dream of inviting the best runners in the world and having “a race along some of the most beautiful roads in the world” is entering its ninth year. Many of the world’s top road runners, including past Olympians, will toe the starting line Saturday at Crescent Beach State Park for the 6.2-mile course that hugs the Maine coast until it reaches the finish line at Fort Williams Park and Portland Head Light.

“There are no prettier roads anywhere in the world than right here,” Samuelson said. “The scenic beauty of the course alone attracts a lot of runners.”

This year’s race features a record 5,500 runners. The field reached its capacity less then two months after registration began. More than $60,000 in prize money will be awarded.

Besides the elite field, the race will include many of the top runners from Maine, who will compete for the unofficial title of Maine’s road-race champion.

Samuelson, the first Olympic gold medalist in the women’s marathon and former world-record holder, didn’t just want another race when she planned the first one in 1998. She felt the race needed a reason to exist. Helping children became the focal point.

The race has helped raise money and awareness for various children’s charities. The symbol of the Portland Headlight beacon led Samuelson and chief sponsor TD Banknorth to christen the race’s motto, “shining the light for Maine youth.” The Boys & Girls Club of Lewiston-Auburn are among the organizations who have benefited.

Having made a pledge to run the race every five years, Samuelson will not run the Beach to Beacon until next year.

Samuelson, 49, still competes and has her eyes set on the 2008 U.S. Olympic Marathon Trials in Boston. Her goal for the Trials is to break 2 hours and 50 minutes at age 50.

She qualified for the Trials last year with a 2:46:26 in Minneapolis.

“I’m thinking it would be nice to end my career where I started my career,” Samuelson said. “I just need to stay healthy.”

She burst onto the world stage with a stunning victory in the 1979 Boston Marathon while still a student at Bowdoin College, setting an American record. She repeated at Boston in 1983 when she set her first world record.

After qualifying for the U.S. Olympic team with a gutsy performance 17 days after knee surgery, she then ran away from the field at the 1984 Olympics in Los Angeles.

Samuelson broke the world record in Chicago in 1985 with a time of 2:21:21. No American ran a faster time until 2003.

Samuelson still owns four of the seven fastest times ever recorded in the women’s marathon by an American.